1. Technical Field
The disclosure is related generally to turbine systems. More particularly, the disclosure is related to a lube oil supply system of a turbine system and method of regulating lube oil temperatures within a turbine system.
2. Related Art
Lube oil systems for turbine systems may aid in the prevention of mechanical wear in the components (e.g., generators, bearings, gears) of the turbine system. More specifically, lube oil systems may provide a consistent and steady flow of oils to turbine system components in order to lubricate, clean component contact surfaces and/or to remove heat generated by moving and stationary turbine system components. The temperature of the lube oil flowing through the components of the turbine system may be dependent, at least in part, on the operational characteristics (e.g., temperature) of the turbine system and the turbine system components. As a result, conventional lube oil systems may include a heat exchanger, which may regulate the temperature of the lube oil depending on the operational characteristic of the turbine system. Using cooling fluid (e.g., water or other cooling fluid), the heat exchanger of the lube oil system may regulate the temperature of the lube oil before it flows to the turbine system. In a closed-loop fluid supply system, the cooling fluid may be provided from a supply tank included in the lube oil system or packaged as part of a separate plant cooling water system and may continuously recirculate the cooling fluid to the heat exchanger. Alternatively, in an open-loop fluid supply system, cooling fluid may be continuously provided and disregarded from a source outside of the lube oil system, including, cooling towers, lakes, oceans and rivers. In contrast to closed-loop fluid supply system, where the cooling fluid is substantially filtered, the cooling fluid in an open-loop fluid supply system may include contaminants (e.g., debris, dirt/sand particles, etc.) that can harm the heat exchanger. More specifically, during the operation of a lube oil system that includes an open-loop fluid supply system, contaminants of the cooling fluid may cause fouling within the heat exchanger during high operational temperatures of the lube oil system. The high operational temperatures cause the contaminants in the cooling fluid to breakdown and substantially “coat” the heat exchanger. As a result, the heat transfer performance of the heat exchanger may be negatively affected by the fouling and, the temperature regulation of the lube oil may also be negatively affected. This may ultimately decrease the performance of the turbine system. To prevent fouling within the heat exchanger, the cooling fluid must regulate the temperature of the lube oil and/or the heat exchanger.
Conventional lube oil systems include components to minimize the risk of fouling within the heat exchanger during high operational temperatures of the lube oil system. For example, one conventional lube oil system may include a 3-way valve positioned on the fluid lines of either the cooling fluid supply or the lube oil supply. By adjusting the positioning of the 3-way valve, the temperature of the lube oil and/or the heat exchanger may be regulated. However, the use of a 3-way valve may cause pressure drops in the fluid lines that may hinder flow rate, and may negatively impact the operational performance of the lube oil system and/or the turbine system.
Another example of a convention lube oil system may include a 2-way valve on the fluid lines of either the cooling fluid supply or the lube oil supply. By adjusting the positioning of the 2-way valve, the flow rate of the respective fluid (e.g., cooling fluid, lube oil) may be adjusted to regulate the temperature of the lube oil and/or the heat exchanger. However, the use of a single 2-way valve in the conventional lube oil system may prevent control of the flow of both the cooling fluid and the lube oil. As a result, dependent upon where the 2-way valve is positioned, the risk of fouling during high operational temperatures of the lube oil system may be slightly reduced, but may not be significantly reduced or eliminated.